package org.apache.lucene.search;

/**
 * Copyright 2005 Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.IOException;

/** A scorer that matches no document at all. */
class NonMatchingScorer extends Scorer {
    public NonMatchingScorer() {
        super(null);
    } // no similarity used

    public int doc() {
        throw new UnsupportedOperationException();
    }

    public boolean next() throws IOException {
        return false;
    }

    public float score() {
        throw new UnsupportedOperationException();
    }

    public boolean skipTo(int target) {
        return false;
    }

    public Explanation explain(int doc) {
        Explanation e = new Explanation();
        e.setDescription("No document matches.");
        return e;
    }
}
